Temporal based motion sensor reporting

ABSTRACT

Methods and systems may include a motion sensor and logic to sample an output signal of the motion sensor. The logic can also be configured to track an amount of time the motion sensor is triggered based on the output signal, and transmit the amount of time over a wireless link on a periodic basis.

RELATED APPLICATION

This application is a continuation application and claims the benefitunder 35 U.S.C. 120 of U.S. patent application No. 12/969,318 filed Dec.15, 2010, which was allowed on May 3, 2013, the entire content of whichis incorporated herein by reference.

BACKGROUND

1. Technical Field

Embodiments generally relate to motion sensing. More particularly,embodiments relate to tracking the amount of time wireless motionsensors are triggered.

2. Discussion

Conventional motion sensing solutions may involve the use of eventdriven motion sensors that are networked with an aggregator, whereineach sensor begins reporting “motion events” to the aggregator whenmotion is first sensed and thereafter on a prescribed schedule (e.g.,every six seconds) until the motion is no longer sensed. The aggregatormay then use software to determine total motion time in the area coveredby the remote sensors based on the motion events received from thesensors. While such an approach can be suitable under certaincircumstances, there still remains considerable room for improvement.For example, event driven sensing may be prone to false, periodic and/orintermittent triggers, which can have a negative impact on accuracy.Moreover, continually reporting data to the aggregator couldsignificantly decrease the battery life of the sensors, particularly inthe case of wirelessly networked sensors.

BRIEF DESCRIPTION OF THE DRAWINGS

The various advantages of the embodiments of the present invention willbecome apparent to one skilled in the art by reading the followingspecification and appended claims, and by referencing the followingdrawings, in which:

FIG. 1 is a flowchart of an example of a method of determining theamount of time a motion sensor is triggered according to an embodiment;

FIG. 2 is a signal diagram of an example of an output signal of a motionsensor according to an embodiment;

FIG. 3 is a flowchart of an example of a method of using a counter valueto determine the amount of time a motion sensor is triggered accordingto an embodiment;

FIG. 4 is a flowchart of an example of a method of reporting the amountof time a motion sensor is triggered according to an embodiment;

FIG. 5 is a block diagram of an example of a system according to anembodiment; and

FIG. 6 is an exploded perspective view of an example of a motion sensorassembly according to an embodiment.

DETAILED DESCRIPTION

Embodiments may include a system having a motion sensor and logic tosample an output signal of the motion sensor, and track the amount oftime the motion sensor is triggered based on the output signal. Thelogic can also transmit the amount of time over a wireless link on aperiodic basis.

Embodiments can also include a computer readable storage medium having aset of stored instructions which, if executed by a processor, cause acomputer to sample an output signal of a motion sensor, and track theamount of time the motion sensor is triggered based on the outputsignal. The instructions, if executed, may also cause a computer totransmit the amount of time over a wireless link on a periodic basis.

Other embodiments may involve a method in which an output signal of apassive infrared motion sensor is sampled. The method can also providefor conducting a repetitive increment of a counter value in response toa first trigger event in the output signal, wherein the first triggerevent includes a rising edge transition and corresponds to detectedmotion. The repetitive increment can be conducted in accordance with aclock timer. The method may also provide for discontinuing therepetitive increment in response to a second trigger event in the outputsignal, wherein the second trigger event includes an expiration of afirst idleness period after a falling edge transition and the fallingedge transition corresponds to a lack of detected motion. In addition,the method may involve adding the counter value to a cumulative value inresponse to the second trigger event, wherein the cumulative valueindicates an amount of time the passive infrared motion sensor istriggered. The method can also provide for activating a wirelessinterface, transmitting the cumulative value via the wireless interface,and deactivating the wireless interface in response to receiving anacknowledgement of the cumulative value transmission.

Turning now to FIG. 1, a method 12 of determining the amount of time amotion sensor is triggered is shown. The method 12 and other methodsdescribed herein may be implemented in executable software as a set oflogic instructions stored in a machine- or computer-readable medium of amemory such as random access memory (RAM), read only memory (ROM),programmable ROM (PROM), firmware, flash memory, etc., infixed-functionality hardware logic using circuit technology such asapplication specific integrated circuit (ASIC), complementary metaloxide semiconductor (CMOS) or transistor-transistor logic (TTL)technology, or any combination thereof. For example, computer programcode to carry out operations shown in method 12 may be written in anycombination of one or more programming languages, including an objectoriented programming language such as Java, Smalltalk, C++ or the likeand conventional procedural programming languages, such as the “C”programming language or similar programming languages. In particular,the method 12 can be implemented on a logic board containing the motionsensor.

Processing block 14 provides for sampling an output signal of the motionsensor. The amount of time that the motion sensor is triggered may betracked at block 16, wherein illustrated block 18 provides fortransmitting the amount of time over a wireless link on a periodicbasis. As will be discussed in greater detail, tracking the amount oftime that the motion sensor is triggered can obviate accuracy concernsassociated with event driven sensing, and transmitting the amount oftime on a periodic basis can provide substantial power savings andsignificantly extended battery life.

FIG. 2 shows an output signal 10 of a motion sensor such as a passiveinfrared (PIR, pyroelectric) motion sensor that does not emit energy andcan detect the movement of nearby individuals by reading relative energy(e.g., heat) changes in the field of view of the sensor. Generally, theillustrated output signal 10 transitions to a high value (i.e., exhibitsa rising edge transition, indicated with an “O”) when motion is detectedby the sensor. The illustrated output signal 10 remains high untilmotion is no longer detected, wherein a lack of detected motion causesthe output signal 10 to transition to a low value (i.e., exhibit afalling edge transition, indicated with an “X”). Alternative signalingschemes such as an inverted scheme in which a rising edge transitioncorresponds to a lack of detected motion and a falling edge transitioncorresponds to detected motion, or a level based scheme in which onevoltage level corresponds to detected motion and another voltage levelcorresponds to a lack of detected motion, might also be used.

FIG. 3 shows a detailed method 20 of using a counter value to determinethe amount of time a motion sensor is triggered. With continuingreference to FIGS. 2 and 3, processing block 22 provides for determiningwhether the sampled output signal is high. If so, illustrated block 24determines whether a counter timer is deactivated. In this regard, themotion sensor or other system component may be equipped with a clockthat provides a timer output that might be used in the tracking process.Moreover, in periods of extended idleness (e.g., upon expiration ofidleness period A.DELTA.t.sub.1), the timer could be deactivated inorder to conserve power and extend battery life. If it is determinedthat the timer has been deactivated, block 26 can provide for activatingthe clock timer and block 28 can provide for resetting a counter value(e.g., “timer_count” variable).

Illustrated block 30 conducts an increment of the counter value inaccordance with the clock timer. For example, if the clock timer has anoperating frequency of 2 Hz, every ½ second the counter value would beincremented by one. A determination may be made at block 32 as towhether the output signal is low (i.e., whether a falling edgetransition has occurred). If not, the increment of the counter value atblock 30 can be repeated. If the output signal has transitioned to thelow state, the illustrated method 20 enables a determination to be madeas to whether the transition corresponds to a “false positive”condition. In particular, another idleness period (e.g., idleness period.DELTA.t.sub.2) may be effectively added to the end of each falling edgetransition to ensure that the transition was not associated with ascenario in which the infrared footprint of an individual is not movingfast enough or the individual has stopped momentarily.

Thus, illustrated block 34 stores the counter value to an intermediatevalue (e.g., “last_falling_edge” variable) locally at the motion sensor.If it is determined at block 36 that the idleness period .DELTA.t.sub.2has not expired, an increment of the counter value may be conducted atblock 38 and a determination can be made at block 40 as to whether theoutput signal is still low. If so, the sensor idleness check at block 36may be repeated. Otherwise, the illustrated process returns to therepetitive increment of the counter value at block 30. Thus, if, as inthe case of falling edge transition 42, the output signal 10 transitionshigh again before expiration of the idleness period .DELTA.t.sub.2, theincrement of the counter value can continue as if the falling edgetransition 42 had not occurred.

If, on the other hand, the output signal 10 does not transition highagain before expiration of the idleness period .DELTA.t.sub.2, as in thecase of falling edge transition 44, the illustrated method 20 enablesthe most recent falling edge transition 44 to be used in thedetermination of the amount of time that the motion sensor has beentriggered. In particular, block 46 provides for adjusting theintermediate value, which is effectively the counter value of the mostrecent falling edge transition previously stored in block 34, based onthe operating frequency of the clock timer in order to obtain the amountof time in seconds. For example, if the frequency of the clock timer is2 Hz, the counter value is incremented every ½ second and the adjustmentat block 46 may involve dividing the intermediate value by two. If, onthe other hand, the frequency of the clock timer is 3 Hz, the adjustmentat block 46 could divide the intermediate value by three. Illustratedblock 48 adds the intermediate value to a cumulative value (e.g.,“total_motion_time”), which indicates the total amount of time themotion sensor is triggered. An intermediate value can also be calculatedfor the trigger sequence 45 of the output signal 10 and added to thecumulative value to update the amount of time the motion sensor istriggered.

As already noted, the clock timer can be deactivated during times ofextended idleness (e.g., upon expiration of idleness period.DELTA.t.sub.1) to reduce power consumption and increase battery life.In particular, if it is determined at block 22 that the output signal islow, block 50 may determine whether the clock timer is activated. If theclock timer activated, a determination can be made at block 52 as towhether the extended idleness period .DELTA.t.sub.1 has expired. If so,illustrated block 54 provides for deactivating the clock timer. Adetermination may be made at block 56 as to whether to terminate themethod 20 or return to block 22.

FIG. 4 demonstrates that further power savings may be achieved bytransmitting the amount of time on a periodic basis in method 58. Forexample, illustrated block 60 provides for determining whether anaccumulation period has expired. The accumulation period might be arelatively long period of time such as thirty minutes so as to takeadvantage of the deactivation of a wireless interface, which can beactivated at block 62. Alternatively, a wired interface could be used.The amount of time that the motion sensor has been triggered may betransmitted via the wireless interface at block 64. The transmissionmight be directed to a data aggregator associated with a system thatcollects information about occupants' activity in their homes andevaluates the activity in terms of nutrition, activity and cognitionindices. Illustrated block 66 provides for determining whether anacknowledgement (ACK) has been received from the intended recipient ofthe amount of time transmission. If no acknowledgement has been receivedand it is determined at block 68 that a timeout has not occurred, thesystem may check again for an acknowledgement. If a timeout has occurredor an acknowledgement has been received, block 70 provides fordeactivating the wireless interface.

FIG. 5 shows a system 72 in which a motion sensor assembly 74 isconfigured to determine the amount of time 76 that a PIR sensor 78 hasbeen triggered, and transmit the amount of time 76 to an aggregator 80on a periodic basis. The motion sensor assembly 74 might be one ofseveral passive motion sensing devices positioned throughout the home ofan individual such as a senior, wherein the amount of time 76 theindividual spends in a given area can be indicative of nutritional,cognitive, and/or activity state. For example, if the motion sensorassembly 74 is installed in a kitchen and the amount of time 76indicates that the individual has spent a relatively short amount oftime in the field of view of the PIR sensor 78, a determination could bemade that the individual is not eating sufficiently. Alternatively, ifthe motion sensor assembly 74 is installed in a bathroom and the amountof time 76 indicates that the individual has spent a relatively longamount of time in the field of view of the PIR sensor 78, adetermination might be made that the individual is having healthproblems related to bathroom activity.

As already noted, the amount of time 76 can be accumulated on the motionsensor assembly 74 using a clock timer, counter value, intermediatevalue and a cumulative value, which identifies the amount of time 76that the PIR sensor 78 has been triggered during the accumulationperiod. The illustrated motion sensor assembly 74 includes a processor(e.g., embedded microcontroller, general purpose central processingunit/CPU) 82, memory 84, a wireless interface 86, a battery 88, a clock89, and one or more other controllers 90. The processor 82 may includeone or more processor cores (not shown) capable of executing a set ofstored logic instructions to implement methods such as a portion or allof the method 12 (FIG. 1), the method 20 (FIG. 3), and/or the method 58(FIG. 4), already discussed.

The memory 84 might include RAM and/or non-volatile memory suitable forstoring counter values, intermediate values and cumulative valuesrepresentative of the amount of time that the PIR sensor 78 istriggered. The wireless interface 86 could provide off-platformcommunication functionality in a wide variety of modes such as cellulartelephone (e.g., W-CDMA (UMTS), CDMA2000 (IS-856/IS-2000), etc.), WiFi(e.g., IEEE 802.11, 1999 Edition, LAN/MAN Wireless LANS), Low-RateWireless PAN (e.g., IEEE 802.15.4-2006, LR-WPAN), Bluetooth (e.g., IEEE802.15.1-2005, Wireless Personal Area Networks), WiMax (e.g., IEEE802.16-2004, LAN/MAN Broadband Wireless LANS), Global Positioning System(GPS), spread spectrum (e.g., 900 MHz), and other radio frequency (RF)telephony modes. In addition, the other controllers 90 could providesupport for user interface devices such as a display, keypad, mouse,etc. in order to allow a user to interact with and perceive informationfrom the motion sensor assembly 74. Thus, the amount of time 76 andother information could also be output via the other controllers 90.

Turning now to FIG. 6, a perspective view of a motion sensor assembly 74includes a battery 84 and a logic board 94 having a PIR sensor 78mounted thereon, wherein the battery 84, logic board 94 and PIR sensor78 are disposed within a protective housing 92. The logic board 94 canalso include a processor, wireless interface, memory and othercontrollers, wherein the motion sensor assembly 74 samples an outputsignal of the PIR sensor 78, tracks the amount of the PIR sensor 78 istriggered based on the output signal, and transmits the amount of timeover a wireless link on a periodic basis, as already discussed.

Thus, the techniques described herein can significantly extend thebattery life of motion sensors and improve the accuracy of monitoringsensors used for daily active living. For example, reducing falsepositives in a daily active living monitoring system can in turn reduceunnecessary, intrusive and costly interventions by monitoring staff.Moreover, an increase in the confidence of the alerts generated can beachieved.

Embodiments of the present invention are applicable for use with alltypes of semiconductor integrated circuit (“IC”) chips. Examples ofthese IC chips include but are not limited to processors, controllers,chipset components, programmable logic arrays (PLA), memory chips,network chips, and the like. In addition, in some of the drawings,signal conductor lines are represented with lines. Some may be thicker,to indicate more constituent signal paths, have a number label, toindicate a number of constituent signal paths, and/or have arrows at oneor more ends, to indicate primary information flow direction. This,however, should not be construed in a limiting manner. Rather, suchadded detail may be used in connection with one or more exemplaryembodiments to facilitate easier understanding of a circuit. Anyrepresented signal lines, whether or not having additional information,may actually comprise one or more signals that may travel in multipledirections and may be implemented with any suitable type of signalscheme, e.g., digital or analog lines implemented with differentialpairs, optical fiber lines, and/or single-ended lines.

Example sizes/models/values/ranges may have been given, althoughembodiments of the present invention are not limited to the same. Asmanufacturing techniques (e.g., photolithography) mature over time, itis expected that devices of smaller size could be manufactured. Inaddition, well known power/ground connections to IC chips and othercomponents may or may not be shown within the figures, for simplicity ofillustration and discussion, and so as not to obscure certain aspects ofthe embodiments of the invention. Further, arrangements may be shown inblock diagram form in order to avoid obscuring embodiments of theinvention, and also in view of the fact that specifics with respect toimplementation of such block diagram arrangements are highly dependentupon the platform within which the embodiment is to be implemented,i.e., such specifics should be well within purview of one skilled in theart. Where specific details (e.g., circuits) are set forth in order todescribe example embodiments of the invention, it should be apparent toone skilled in the art that embodiments of the invention can bepracticed without, or with variation of, these specific details. Thedescription is thus to be regarded as illustrative instead of limiting.

The term “coupled” may be used herein to refer to any type ofrelationship, direct or indirect, between the components in question,and may apply to electrical, mechanical, fluid, optical,electromagnetic, electromechanical or other connections. In addition,the terms “first”, “second”, etc. might be used herein only tofacilitate discussion, and carry no particular temporal or chronologicalsignificance unless otherwise indicated.

Those skilled in the art will appreciate from the foregoing descriptionthat the broad techniques of the embodiments of the present inventioncan be implemented in a variety of forms. Therefore, while theembodiments of this invention have been described in connection withparticular examples thereof, the true scope of the embodiments of theinvention should not be so limited since other modifications will becomeapparent to the skilled practitioner upon a study of the drawings,specification, and following claims.

1-20. (canceled)
 21. A method for accurately tracking an amount of timea motion sensor is triggered, the method being implemented in a computerthat includes one or more processors, the method comprising: monitoringan output signal of the motion sensor, the output signal comprisinginformation related to motion detected by the motion sensor; tracking afirst time period for which the motion sensor is triggered based on theoutput signal, the first time period indicative of an amount of timebetween a first time at which the output signal indicates a detection ofmotion and a second time at which the output signal indicates a lack ofmotion; and storing the first time period.
 22. The method of claim 21,the method further comprising: adding the first time period to acumulative time period; and transmitting the cumulative time period. 23.The method of claim 22, the method further comprising: tracking a secondtime period for which the motion sensor is triggered based on the outputsignal, the second time period indicative of an amount of time between athird time at which the output signal indicates the detection of motionand a fourth time at which the output signal indicates the lack ofmotion; adding the second time period to the cumulative time period; andtransmitting the cumulative time period.
 24. The method of claim 23, themethod further comprising: transmitting the cumulative time period overa wireless link on a periodic basis.
 25. The method of claim 21, themethod further comprising: determining, after the first time, whetherthe output signal indicates the lack of motion; determining that theoutput signal indicates the lack of motion at the second time;determining whether the output signal continues to indicate the lack ofmotion for a predetermined time period after the second time;determining that the motion is no longer detected by the motion sensorat the second time based on determining that the output signal continuesto indicate the lack of motion for the predetermined time period afterthe second time; and storing the first time period based on determiningthat the motion is no longer detected by the motion sensor at the secondtime.
 26. The method of claim 21, the method further comprising:determining whether the output signal indicates the detection of motionor the lack of motion based on a voltage level associated with theoutput signal, wherein a first range of voltage levels indicate thedetection of motion and a second range of voltage levels indicate thelack of motion; determine that the output signal indicates the detectionof motion when the voltage level associated with the output signal iswithin the first range; and determine that the output signal indicatesthe lack of motion when the voltage level associated with the outputsignal is within the second range.
 27. A non-transitory computerreadable medium comprising a set of stored instructions which, ifexecuted by one or more processors, cause a computer to: monitor anoutput signal of a motion sensor, the output signal comprisinginformation related to motion detected by the motion sensor; track afirst time period for which the motion sensor is triggered based on theoutput signal, the first time period indicative of an amount of timebetween a first time at which the output signal indicates a detection ofmotion and a second time at which the output signal indicates a lack ofmotion; and store the first time period.
 28. A system for accuratelytracking an amount of time a motion sensor is triggered, the systemcomprising: the motion sensor; a memory; and one or more processorsconfigured to: monitor an output signal of the motion sensor, the outputsignal comprising information related to motion detected by the motionsensor; track a first time period for which the motion sensor istriggered based on the output signal, the first time period indicativeof an amount of time between a first time at which the output signalindicates a detection of motion and a second time at which the outputsignal indicates a lack of motion; and store the first time period inthe memory.